[CHORES] Delete unused app

helloworld/tests.py

-from django.test import TestCase
-from django.http import HttpRequest
-from .views import helloworld
-
-class HelloWorldTest(TestCase):
-	def test_donation_url_exist(self):
-		response = helloworld(HttpRequest())
-		html_response = response.content.decode('utf8')
-		self.assertIn("Hello World1",html_response)